MQTT publisher:
import network, time
from machine import Pin, UART
from umqtt.simple import MQTTClient
#connect pico W to internet
ssid = "ITEK 2nd"
password = "2nd_Semester_F23v"
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(ssid, password)
while not wlan.isconnected():
print('waiting to connect:')
time.sleep(1)
ip = wlan.ifconfig()[0]
gpsModule = UART(1, baudrate=9600, tx=Pin(4), rx=Pin(5), timeout=500)
#init
#MQTT parameters
broker = 'test.mosquitto.org'
client_id = 'eaaa_pico_w_gps'
topic = "eaaa_gps_data"
def mqtt_connect():
client = MQTTClient(client_id, broker, keepalive=3600)
client.connect()
print('Connected to %s MQTT Broker' % broker)
return client
#initialise an MQTT client
client = mqtt_connect()
#publish GPS data via the MQTT client
while True:
buff = gpsModule.readline()
if buff:
buff = buff.decode()
buff_array = buff.split(',')
if buff_array[0] == '$GNGGA':
client.publish(topic, buff)
MQTT Subscriber:
# Receiving messages via MQTT
import random
import time
from paho.mqtt import client as mqtt_client
# Define broker parameters
broker= 'test.mosquitto.org' #use external broker
m_port = 1883
topic = "eaaa_gps_data"
client_id = f'eaaa-mqtt-{random.randint(0, 1000)}' #genetate client ID
with prefix
def connect_mqtt() -> mqtt_client:
def on_connect(client, userdata, flags, rc):
if rc == 0:
print("Connected to MQTT Broker!")
else:
print("Failed to connect, return code %d\n", rc)
client = mqtt_client.Client(client_id) # Set Connecting Client ID
#
client.username_pw_set(username, password) - note: Password not
configures in broker
client.on_connect = on_connect
client.connect(broker,m_port)
return client
def subscribe(client: mqtt_client):
def on_message(client, userdata, msg):
print(f"Received `{msg.payload.decode()}` from `{msg.topic}`
topic")
client.subscribe(topic)
client.on_message = on_message
def run():
client = connect_mqtt()
subscribe(client)
client.loop_forever()
if __name__ == '__main__':
run()